<!DOCTYPE html>
<html>

	<head>
		<meta charset="utf-8" />
		<title></title>
	</head>

	<body>
		<button onclick="a()">动次动词</button>
		<script type="text/javascript">
			function a() {
				for(var j = 10; j > 0; j--) {

					for(var i = j; i > 0; i--) {
						document.write("☆");
					}
					document.write("<br />");
				}

			}
		</script>
	</body>

</html>